This proposed study will use data from the 2007 National Roadside Survey (NRS), a recently completed data set representative of the drinking condition of weekend U.S. drivers and their passengers. The 2007 NRS includes a passenger survey synchronized with a driver survey, the 2007 NRS provides a unique opportunity to gain knowledge about the understudied role of passengers in impaired driving, aiming for a better understanding of the factors and mechanisms by which a passenger could become either a risk or a prevention factor for impaired driving. Furthermore, by providing information on the drivers'drinking patterns as well as on his/her drug consumption, this study will also provide much needed information on the characteristics of passengers riding with drivers showing AUDs and/or drug consumption. The information provided by this study will fill a current gap in knowledge that could be used to develop new avenues for interventions, in particular for populations most vulnerable to riding with a drinking driver. PUBLIC HEALTH RELEVANCE: This study will gain knowledge about the understudied role of passengers in impaired driving, aiming for a better understanding of the factors and mechanisms by which a passenger could become either a risk or a prevention factor for impaired driving. We hope the information provided by this study will fill a current gap in knowledge that could be used to develop new avenues for interventions, in particular for populations most vulnerable to riding with a drinking driver.